Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

"Edible Optics" Could Make Food Safer

08.08.2008
Tufts University scientists have shown that it is possible to design biologically active, biodegradable optical devices – made from silk and needing no refrigeration - with applications in medicine, health, the environment and communications. For example, edible optical sensors could detect harmful bacteria in produce, and be consumed right along with the food if it were safe.

Imagine an edible optical sensor that could be placed in produce bags to detect harmful levels of bacteria and consumed right along with the veggies. Or an implantable device that would monitor glucose in your blood for a year, then dissolve.

Scientists at Tufts University's School of Engineering have demonstrated for the first time that it is possible to design such "living" optical elements that could enable an entirely new class of sensors. These sensors would combine sophisticated nanoscale optics with biological readout functions, be biocompatible and biodegradable, and be manufactured and stored at room temperatures without use of toxic chemicals. The Tufts team used fibers from silkworms to develop the platform devices.

Tufts University has filed a number of patent applications on silk-based optics and is actively exploring commercialization opportunities.

... more about:
»Biomedical »Quality »Sensor »biodegradable

"Sophisticated optical devices that are mechanically robust yet fully biodegradable, biocompatible and implantable don't exist today," said principal investigator Fiorenzo Omenetto, associate professor of biomedical engineering and associate professor of physics. "Such systems would greatly expand the use of current optical technologies in areas like human and livestock health, environmental monitoring and food quality."

"For example, at a low cost, we could potentially put a bioactive silk film in every bag of spinach, and it could give the consumer a readout of whether or not E. coli bacteria were in the bag—before the food was consumed," explained David Kaplan, professor and chair of the biomedical engineering department.

The Tufts research was published in a recent paper in Biomacromolecules by Brian D. Lawrence, graduate student in biomedical engineering; Mark Cronin-Golomb, associate professor, biomedical engineering; Irene Georgakoudi, assistant professor, biomedical engineering; Kaplan, and Omenetto.

(http://pubs.acs.org/cgi-bin/article.cgi/bomaf6/2008/9/i04/pdf/bm701235f.pdf).

Optics – the science of light and its interaction with matter – has fascinated generations of scientists such as Sir Isaac Newton. Current optical device platforms are based primarily on glass, semiconductors, plastics or polymers. But the harsh solvents and extreme temperatures needed for manufacture make it impossible to incorporate bioactive sensing components into the devices. Chemical residues and lack of biodegradability also limit environmental and medical applications. Furthermore, biological components typically need to be stored at controlled temperatures to retain their activity.

The possibility of integrating optical readout and biological function in a single biocompatible device unconstrained by these limitations is tantalizing. Silk optics has captured the interest of the Defense Department, which has funded and been instrumental in enabling rapid progress on the topic. The Defense Advanced Research Projects Agency (DARPA) awarded Tufts a research contract in 2007 and is funding Tufts and others on groundbreaking projects that could someday result in biodegradable optical sensing communications technology.

Silk a Natural for Biocompatible Optics
Silk proteins are, literally, a natural for integrating optical and biological functions. They can be processed in water at ordinary temperatures and patterned on the nanoscale to generate a wide range of optical elements, including ultrathin films, thick films, and nanoscale and large-diameter fibers. Silk proteins also offer excellent surface quality and transparency, which are perquisites for high-quality optics. Equally important, they are mechanically robust.

"Silks spun by spiders and silkworms represent the strongest and toughest natural fibers known. They offer many opportunities for functionalization, processing and biological integration when compared to conventional polymers," said Kaplan, an expert on natural biomaterials like silk.

To form the devices, Tufts scientists boiled cocoons of the Bombyx mori silkworm in a water solution and extracted the glue-like sericin proteins. The purified silk protein solution was ultimately poured onto negative molds of ruled and holographic diffraction gratings with spacing as fine as 3600 grooves/mm. The cast silk solution was air dried to create solid fibroin silk films that were cured in water, dried and optically evaluated. A similar process was followed to create lenses, microlens arrays and holograms. Film thicknesses from 10 to 100 µm were characterized for transparency and optical quality.

The variety and quality of the optical elements compared favorably with conventional platforms and outperformed other commonly used biopolymers.

However, the most compelling feature of the platform, according to the Tufts researchers, is that the elements are prepared, processed and optimized in all-aqueous environments and at ambient temperature. This makes possible the inclusion of sensitive biological 'receptors' within the solution that stay active after the solution has hardened into a free-standing silk optical element.

No Refrigeration Needed
The Tufts team embedded three very different biological agents in the silk solution: a protein (hemoglobin), an enzyme (horseradish peroxidase) and an organic pH indicator (phenol red). In the hardened silk optical element, all three agents maintained their activity for long periods when simply stored on a shelf. "We have optical devices embedded with enzymes that are still active after almost a year of storage at room temperature. This is amazing given that the same enzyme becomes inactive if forgotten and left unrefrigerated for a few days," said Omenetto."

Researchers also found that it was possible to alter the propagation of light through the silk optic as a function of the embedded dopant to create an optical signal of the biological activity.

Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university's schools is widely encouraged.

Kim Thurler | Newswise Science News
Further information:
http://www.tufts.edu

Further reports about: Biomedical Quality Sensor biodegradable

More articles from Life Sciences:

nachricht Discovery of a Key Regulatory Gene in Cardiac Valve Formation
24.05.2017 | Universität Basel

nachricht Carcinogenic soot particles from GDI engines
24.05.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>